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Related Concept Videos

Chemical Equilibria: Systematic Approach to Equilibrium Calculations01:21

Chemical Equilibria: Systematic Approach to Equilibrium Calculations

1.4K
Equilibrium calculations for systems involving multiple equilibria are often complex. For example, to calculate the solubility of a sparingly soluble salt in an aqueous solution in the presence of a common ion, one must consider all the equilibria in this solution. Calculations for these systems can be complicated and tedious, so a systematic approach with a series of steps is often helpful. The process is detailed below.
The first step is to identify all the chemical reactions involved, The...
1.4K
Free Energy Changes for Nonstandard States03:25

Free Energy Changes for Nonstandard States

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The free energy change for a process taking place with reactants and products present under nonstandard conditions (pressures other than 1 bar; concentrations other than 1 M) is related to the standard free energy change according to this equation:
13.3K
Homogeneous Equilibria for Gaseous Reactions02:15

Homogeneous Equilibria for Gaseous Reactions

28.5K
Homogeneous Equilibria for Gaseous Reactions
For gas-phase reactions, the equilibrium constant may be expressed in terms of either the molar concentrations (Kc) or partial pressures (Kp) of the reactants and products. A relation between these two K values may be simply derived from the ideal gas equation and the definition of molarity. According to the ideal gas equation:
28.5K
Calculating Equilibrium Concentrations02:05

Calculating Equilibrium Concentrations

52.4K
Being able to calculate equilibrium concentrations is essential to many areas of science and technology—for example, in the formulation and dosing of pharmaceutical products. After a drug is ingested or injected, it is typically involved in several chemical equilibria that affect its ultimate concentration in the body system of interest. Knowledge of the quantitative aspects of these equilibria is required to compute a dosage amount that will solicit the desired therapeutic effect.
A more...
52.4K
Calculating the Equilibrium Constant02:46

Calculating the Equilibrium Constant

37.3K
The equilibrium constant for a reaction is calculated from the equilibrium concentrations (or pressures) of its reactants and products. If these concentrations are known, the calculation simply involves their substitution into the Kc expression.
For example, gaseous nitrogen dioxide forms dinitrogen tetroxide according to this equation:
37.3K
Chemical Equilibria: Redefining Equilibrium Constant01:20

Chemical Equilibria: Redefining Equilibrium Constant

1.1K
The effect of an inert salt on the solubility of a sparingly soluble salt is known as the salt effect. The degree of the salt effect varies with the ionic strength of the solution, which in turn depends on the activity of the species in the solution. The activity is expressed as the product of concentration and the activity coefficient of the species.
To calculate the equilibrium constants of solutions of moderately high ionic strength, one must account for the salt effect. This redefined...
1.1K

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Phase Equilibrium Relations in the Sc2O3-Ga2O3 System.

S J Schneider, J L Waring

    Journal of Research of the National Bureau of Standards. Section A, Physics and Chemistry
    |October 4, 2019
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    This study determined the phase equilibrium diagram for the Scandium Oxide-Gallium Oxide (Sc₂O₃-Ga₂O₃) system, identifying two intermediate binary phases and their properties at high temperatures.

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    Area of Science:

    • Materials Science
    • Ceramics
    • Phase Equilibria

    Background:

    • Understanding the phase behavior of oxide systems is crucial for developing advanced ceramic materials.
    • Scandium Oxide (Sc₂O₃) and Gallium Oxide (Ga₂O₃) are important components in various high-temperature applications.

    Purpose of the Study:

    • To determine the phase equilibrium diagram for the Sc₂O₃-Ga₂O₃ system.
    • To characterize the intermediate binary phases formed within this system.

    Main Methods:

    • High-temperature experiments utilizing a quenching furnace (up to 1,800 °C) and an induction furnace (higher temperatures).
    • Precise temperature measurements using optical pyrometry and Pt-Rh thermocouples.
    • Analysis of phase formation and stability under varying compositional and thermal conditions.

    Main Results:

    • The melting point of Ga₂O₃ was determined to be 1,795 ±15 °C.
    • Sc₂O₃ did not melt even at 2,405 °C.
    • Two intermediate phases were identified: a high-temperature 6Sc₂O₃·5Ga₂O₃ compound and a solid solution region (55-73 mole % Ga₂O₃).
    • The 6:5 compound melts incongruently at 1,770 ±15 °C and decomposes below 1,700 ±15 °C, exhibiting orthorhombic symmetry.

    Conclusions:

    • The Sc₂O₃-Ga₂O₃ system exhibits complex phase behavior with distinct intermediate phases.
    • The identified phases and their thermal stability provide critical data for the design and application of Sc-Ga-O based ceramics.